diff --git a/test/built-ins/Temporal/PlainDate/prototype/toString/calendar-tostring.js b/test/built-ins/Temporal/PlainDate/prototype/toString/calendar-tostring.js
index 0684a0978c4..75a2e03fbf2 100644
--- a/test/built-ins/Temporal/PlainDate/prototype/toString/calendar-tostring.js
+++ b/test/built-ins/Temporal/PlainDate/prototype/toString/calendar-tostring.js
@@ -3,7 +3,7 @@
 
 /*---
 esid: sec-temporal.plaindate.protoype.tostring
-description: Should always call 'toString' on the calendar once.
+description: Should call 'toString' on the calendar once unless calendarName == 'never'.
 features: [Temporal]
 ---*/
 
@@ -16,13 +16,13 @@ const customCalendar = {
 };
 const date = new Temporal.PlainDate(2000, 5, 2, customCalendar);
 [
-  ["always", "2000-05-02[u-ca=custom]"],
-  ["auto", "2000-05-02[u-ca=custom]"],
-  ["never", "2000-05-02"],
-  [undefined, "2000-05-02[u-ca=custom]"],
-].forEach(([calendarName, expected]) => {
+  ["always", "2000-05-02[u-ca=custom]", 1],
+  ["auto", "2000-05-02[u-ca=custom]", 1],
+  ["never", "2000-05-02", 0],
+  [undefined, "2000-05-02[u-ca=custom]", 1],
+].forEach(([calendarName, expectedResult, expectedCalls]) => {
   calls = 0;
   const result = date.toString({ calendarName });
-  assert.sameValue(result, expected, `calendarName = ${calendarName}: expected ${expected}`);
-  assert.sameValue(calls, 1, `calendarName = ${calendarName}: expected one call to 'toString'`);
+  assert.sameValue(result, expectedResult, `calendarName = ${calendarName}: expected ${expectedResult}`);
+  assert.sameValue(calls, expectedCalls, `calendarName = ${calendarName}: expected ${expectedCalls} call(s) to 'toString'`);
 });
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/toString/calendar-tostring.js b/test/built-ins/Temporal/PlainDateTime/prototype/toString/calendar-tostring.js
new file mode 100644
index 00000000000..9ff60128346
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/toString/calendar-tostring.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.protoype.tostring
+description: Should call 'toString' on the calendar once unless calendarName == 'never'.
+features: [Temporal]
+---*/
+
+let calls;
+const customCalendar = {
+  toString() {
+    ++calls;
+    return "custom";
+  }
+};
+const date = new Temporal.PlainDateTime(2000, 5, 2, 12, 34, 56, 987, 654, 321, customCalendar);
+[
+  ["always", "2000-05-02T12:34:56.987654321[u-ca=custom]", 1],
+  ["auto", "2000-05-02T12:34:56.987654321[u-ca=custom]", 1],
+  ["never", "2000-05-02T12:34:56.987654321", 0],
+  [undefined, "2000-05-02T12:34:56.987654321[u-ca=custom]", 1],
+].forEach(([calendarName, expectedResult, expectedCalls]) => {
+  calls = 0;
+  const result = date.toString({ calendarName });
+  assert.sameValue(result, expectedResult, `calendarName = ${calendarName}: expected ${expectedResult}`);
+  assert.sameValue(calls, expectedCalls, `calendarName = ${calendarName}: expected ${expectedCalls} call(s) to 'toString'`);
+});
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/toString/calendar-tostring.js b/test/built-ins/Temporal/ZonedDateTime/prototype/toString/calendar-tostring.js
new file mode 100644
index 00000000000..d91f9c522b0
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/toString/calendar-tostring.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.protoype.tostring
+description: Should call 'toString' on the calendar once unless calendarName == 'never'.
+features: [Temporal]
+---*/
+
+let calls;
+const customCalendar = {
+  toString() {
+    ++calls;
+    return "custom";
+  }
+};
+const date = new Temporal.ZonedDateTime(3661_987_654_321n, "UTC", customCalendar);
+[
+  ["always", "1970-01-01T01:01:01.987654321+00:00[UTC][u-ca=custom]", 1],
+  ["auto", "1970-01-01T01:01:01.987654321+00:00[UTC][u-ca=custom]", 1],
+  ["never", "1970-01-01T01:01:01.987654321+00:00[UTC]", 0],
+  [undefined, "1970-01-01T01:01:01.987654321+00:00[UTC][u-ca=custom]", 1],
+].forEach(([calendarName, expectedResult, expectedCalls]) => {
+  calls = 0;
+  const result = date.toString({ calendarName });
+  assert.sameValue(result, expectedResult, `calendarName = ${calendarName}: expected ${expectedResult}`);
+  assert.sameValue(calls, expectedCalls, `calendarName = ${calendarName}: expected ${expectedCalls} call(s) to 'toString'`);
+});